Voltage harvester for power distribution system devices

ABSTRACT

The present disclosure provides exemplary embodiments of voltage harvesting devices used in power distribution systems, and provides power distribution system architectures utilizing the voltage harvesting devices. Generally, the voltage harvesting devices transform distribution line AC voltages to produce a low wattage output for distribution system communication and control type devices. The voltage harvesting device can operate whether irrespective of the presence of load current.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/513,855filed Jul. 17, 2019, and claims benefit from U.S. ProvisionalApplication Ser. No. 62/699,426 filed on Jul. 17, 2018 the contents ofboth are incorporated herein in their entirety by reference.

BACKGROUND Field

The present disclosure relates generally to voltage harvesting devicesused in power distribution systems and to power system architecturesutilizing the voltage harvesting devices. The voltage harvesting devicestransform distribution system voltages to power distribution systemcommunication and control type devices that utilize or consume lowpower.

Description of the Related Art

A frequent problem in almost any electrical power distribution system isa momentary disruption of electrical service that may be caused byenvironmental conditions. For example, 1) lightening may strike in thevicinity of power lines, or 2) wind may cause power lines strung betweenpoles to momentarily touch each other or to touch a grounded conductorshorting the lines, or 3) objects may fall across exposed wires andshort the lines. Such events may cause a momentary power line shortcircuit or current surge. Most of these faults are self-correcting anddo not significantly disrupt power distribution. However, some eventsare more serious and can trigger fault-interrupting devices to trip,causing a more serious power disruption.

For example, reclosers are inserted into power lines to protect a powerdistribution system. A recloser is a fault-interrupting device used tosense current, voltage, and/or frequency and isolate faulted portions ofpower distribution conductors. A recloser control device operates arecloser, which can be an electronic controller that operates with a lowwattage input. Typically, such electronic controllers are located withina control box and derive their operating power from a large step-downtransformer on the source side of the power distribution lines therecloser is protecting. This requires separate installation andmaintenance. Electronic controllers located within the recloser as wellas those within a control box also utilize a power storage component tooperate the recloser when the recloser trips. Such stored power sourcesare batteries and capacitors that discharge when the recloser trips. Inaddition, the electronic controllers often include communication devicesthat are also powered by the step-down transformers and back-up batterysupplies. Likewise, live tank devices utilize current transformers toharvest power from line current in order to operate and communicate whenlines are loaded. Utilizing a separate step-down transformer and storedpower source significantly increase the cost and maintenancerequirements to protect the power distribution lines. In the case of alive tank device, requiring lines to be constantly loaded is notrealistic. Thus, a need exists for a compact, lower cost alternative tothe separate step-down transformer, power storage component, and lineload requirements to provide operating power to reclosers, controllers,communication devices, and other devices used in power distributionsystems that rely on low voltage, low power inputs.

SUMMARY

The present disclosure provides exemplary embodiments of voltageharvesting devices used in power distribution systems. The presentdisclosure also provides exemplary embodiments of power distributionsystem architectures utilizing the voltage harvesting devices. Thepresent disclosure also provides exemplary embodiments of transformationcircuits that can be incorporated into the voltage harvesting devices ofthe present disclosure, such as an insulator utilized in conventionalpower distribution system components. Generally, the voltage harvestingdevices and the transformation circuits according to the presentdisclosure transform loaded or unloaded live line voltages to produceoutput power that can be used to supply operating power for powerdistribution system communication and control type devices that utilizeor consume low power.

In an exemplary embodiment, the voltage harvesting device includes ahousing and a transformation circuit embedded in or encased within thehousing. The transformation circuit includes a first impedance componentand a second impedance component arranged as a voltage divider such thatthe transformation circuit has an output AC voltage that is a factor ofabout 0.1 percent to about 5 percent of a source line voltage. In thisexemplary embodiment, the first impedance component is a transformer,and the second impedance component is a resistor.

In another exemplary embodiment, the transformation circuit includes aresistor and a transformer. The transformer has a first terminal forconnecting to a line voltage source and a second terminal connected to afirst terminal of the resistor. The resistor has a second terminal forconnecting to actual ground. A secondary winding of the transformer sitsat line potential so that it has a floating ground reference and outputsan AC voltage in the range of about 25-250 VAC relative to the linevoltage source.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present disclosure and many of theattendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of an exemplary embodiment of a stand-alonevoltage harvesting device housing according to the present disclosure;

FIG. 2 is a side elevation view of the voltage harvesting device of FIG.1;

FIG. 3 is a block diagram of an exemplary embodiment of a circuitincluding the voltage harvesting device of the present disclosure andused to transform a high voltage, high wattage source to a low voltage,low wattage power source for control devices;

FIG. 4 is an exemplary circuit diagram of the internal components of thecircuit of FIG. 3;

FIG. 4A is another exemplary circuit diagram of the internal componentsof the circuit of FIG. 3;

FIG. 5 is a block diagram of another exemplary embodiment of a circuitincluding the voltage harvesting device of the present disclosure andused to transform a high voltage, high wattage source to a low voltage,low wattage power source for control devices;

FIG. 6 is an exemplary circuit diagram of the internal components of thecircuit of FIG. 5;

FIG. 6A is another exemplary circuit diagram of the internal componentsof the circuit of FIG. 5;

FIG. 7 is a block diagram of another exemplary embodiment of a circuitincluding the voltage harvesting device of the present disclosure andused to transform a high voltage, high wattage source to a low voltage,low wattage power source for control devices;

FIG. 8 is an exemplary circuit diagram of the internal components of thecircuit of FIG. 7;

FIG. 8A is an exemplary circuit diagram of the internal components ofthe circuit of FIG. 7;

FIG. 9 is a block diagram of an exemplary embodiment of a single-phasepower distribution system architecture utilizing the voltage harvestingdevice according to the present disclosure, and illustrating the voltageharvesting device connected to a line source and providing an exemplarypower output to a control device with a hard wire connection between thecontrol device and a distribution component;

FIG. 10 is a block diagram of an exemplary embodiment of a single-phasepower distribution system architecture utilizing the voltage harvestingdevice, and illustrating the voltage harvesting device connected to aline source and providing power to a low wattage device with a wirelessconnection between the control device and the distribution component;

FIG. 11 is a side elevation view of an exemplary embodiment of thevoltage harvesting device of FIG. 1 secured to both a utility pole and arecloser and further attached to a control device;

FIG. 12 is a side perspective view of another exemplary embodiment ofthe voltage harvesting device of FIG. 1 secured to a utility pole with across-arm mounting structure and a recloser attached to the voltageharvesting device;

FIG. 13 is a block diagram of an exemplary embodiment of a three-phasepower distribution system architecture utilizing multiple voltageharvesting devices according to the present disclosure, and illustratinga voltage harvesting device connected to a line source of each of threephases and providing power to a control device with a hard wireconnection between the control device and a distribution component;

FIG. 14 is a perspective view of the three-phase power distributionsystem architecture utilizing multiple voltage harvesting devices ofFIG. 13, and illustrating three reclosers attached to three voltageharvesting devices, each of which is connected to a line source of oneof three phases and providing power to a control device which furthercommunicates with at least one distribution component;

FIG. 15 is another exemplary circuit diagram of the internal componentsof the transformation circuitry of FIGS. 4, 6 and 8;

FIG. 16 is another exemplary circuit diagram of the internal componentsof the transformation circuitry of FIGS. 4, 6 and 8;

FIG. 17 is another exemplary circuit diagram of the internal componentsof the transformation circuitry of FIGS. 4, 6 and 8; and

FIG. 18 is another exemplary circuit diagram of the internal componentsof the transformation circuitry of FIGS. 4, 6 and 8.

DETAILED DESCRIPTION

The present disclosure provides exemplary embodiments of voltageharvesting devices used in power distribution systems and powerdistribution system architectures utilizing the voltage harvestingdevices. Generally, the voltage harvesting device according to thepresent disclosure transforms distribution line voltages to produce lowoutput power for power distribution system devices. More specifically,the voltage harvesting device utilizes available high voltage AC onpower distribution conductors to provide low voltage electrical powerfor communication and control type devices without the use or cost of adedicated step-down transformer or other power source, such as a batteryor a capacitor. The voltage harvesting device can be distributedindividually, as part of a power distribution system type component kit,or the voltage harvesting device can be integrated with or into variouspower distribution system type devices. For example, the voltageharvesting device may be incorporated into an insulator and installedwith a recloser.

The power distribution system communication and control type devicescontemplated by the present disclosure include, but are not limited to,recloser control systems, communication systems for smart-gridapplications, pole-mounted remote terminal units (RTUs) that communicatevia cellular, WiFi, Ethernet, mesh networks, and other communicationmethods to a central system, such as SCADA or the IEC 61850 standarddefining communication protocols. For ease of description, the powerdistribution system communication and control type devices may also bereferred to herein collectively as the “control devices” in the pluraland as the “control device” in the singular.

In addition, the power distribution system type components andassociated control devices contemplated by the present disclosureinclude, but are not limited to, line disconnects, fault interrupters,power line monitors, power factor correction devices, and load switchingdevices and other overhead distribution switches, insulators, andarresters. Non-limiting examples of line disconnects includessectionalizers. Non-limiting examples of fault interrupters includebreakers and reclosers. Non-limiting examples of power line monitorsincludes sensors and fault locators. Non-limiting examples of powerfactor correction devices include capacitor switches. Non-limitingexamples of load switching devices include load-break switches. For easeof description, the power distribution system type components may alsobe referred to herein collectively as the “distribution components” inthe plural and the “distribution component” in the singular.

Referring to FIGS. 1-4 and 4A, exemplary embodiments of a voltageharvesting device according to the present disclosure are shown. Thevoltage harvesting device 10 includes voltage harvesting circuitryenclosed in or encased in a housing 50. In one embodiment, the voltageharvesting circuitry includes transformation circuitry 20. In otherembodiments, the voltage harvesting circuitry includes thetransformation circuitry 20 and other circuit components as described inmore detail below.

Referring to FIG. 4, the transformation circuitry 20 is used totransform high voltage AC on high voltage transmission or distributionconductors to an output power level that can be used to supply operatingpower for control devices whether or not there is line current (load) onthe high voltage distribution conductor. In one exemplary embodiment,seen in FIG. 4, the transformation circuitry 20 includes a resistor 22and a transformer 24. The transformer 24 is connected between the linevoltage (Vsource) and one side of the resistor 22, as shown. The otherside of the resistor 22 is connected to pole ground. It is noted thatpole ground is earth ground, actual ground or the like. In the exemplaryembodiment of FIG. 4, the resistor 22 drops the line voltage (Vsource)by a large factor dependent on the source line voltage. For example, a15 kV single phase line voltage, or 8.66 kV, may be dropped by a factorranging between about 4.0 kV to about 7.5 kV across the resistor 22. Thevoltage drop factor may range from about 45-95% of the single phasesource voltage. Further, since the resistor 22 is connected in serieswith the primary winding 24 a of the transformer 24, the resistor 22 issubjected to and configured to handling a high continuous wattage. Thewattage is dependent upon a number of factors including the resistorsize and construction, e.g., parallel configuration. As an example, thehigh continuous wattage may be in the range of between about 20 W toabout 100 W. However, this wattage may change dependent on the linevoltage and the output requirements of the circuit. As a non-limitingexample, for a single-phase line voltage of 8.6 kV the high continuouswattage may be about 60 W.

Referring to FIG. 4A, the transformation circuitry 20 is used totransform high voltage AC on high voltage transmission or distributionconductors to an output power level that can be used to supply operatingpower for control devices whether or not there is line current (load) onthe high voltage distribution conductor. In one exemplary embodiment,seen in FIG. 4A, the transformation circuitry 20 includes a resistor 22and a transformer 24. The resistor 22 is connected between the linevoltage (Vsource) and one side of the primary winding 24 a of thetransformer 24, as shown. The other side of the primary winding 24 a ofthe transformer 24 is connected to pole ground. It is noted that poleground is earth ground, actual ground or the like. In the exemplaryembodiment of FIG. 4A, the resistor 22 drops the line voltage (Vsource)by a large factor dependent on the source line voltage. For example, a15 kV single phase line voltage, or 8.66 kV, may be dropped by a factorranging between about 4 kV to about 7.5 kV across the resistor 22. Thevoltage drop factor may range from about 80-95% of the single phasesource voltage. Further, since the resistor 22 is connected to the linevoltage (Vsource), the resistor 22 is subjected to and configured tohandling a high continuous wattage. The wattage is dependent upon anumber of factors including the resistor size and construction, e.g.,parallel configuration. As an example, the high continuous wattage maybe in the range of between about 20 W to about 100 W. However, thiswattage may change dependent on the line voltage and the outputrequirements of the circuit. As a non-limiting example, for asingle-phase line voltage of 8.6 kV the high continuous wattage may beabout 60 W.

As mentioned previously, the transformer 24 is provided to drop the highvoltage across the resistor 22 by a factor ranging between about 1.2 kVto about 35 kV and, additionally to drop the voltage across thetransformer by a factor ranging between about 1 kV to about 18 kV suchthat the output AC voltage of the entire transformation circuit 20 is afactor of between about 0.1 percent and about 5 percent of the linevoltage source. In the exemplary embodiment described herein the outputAC voltage of the transformation circuit 20 is about 25-250V relative tothe source line voltage (Vsource). It should be understood that forhigher source line voltages, additional resistors 22 or transformers 24may be added in series or parallel in order to accommodate the largervoltage drops and to handle the higher wattages. For example, if theline voltage (Vsource) fed to the resistor 22 is about 8.66 kV, thevoltage drop across the resistor 22 will be about 7.4 kV, and thevoltage drop across the transformer primary is 1.2 kV, then thetransformer 24 may output 48 VAC at about 10 watts of power. However,the properties of the transformer 24 may vary depending upon a number offactors including the source line voltage (Vsource), the high continuouswattage, line impedances, winding impedances, core impedances, thedesired output voltage, the desired output wattage, and other propertiesassociated with the transformer 24. Non-limiting examples of thetransformer properties include: size of the core of the transformer, thematerial used to form the core, the gauge of the wire windings aroundthe core, the insulation surrounding the wire windings, and the numberof windings for the primary and secondary (i.e., turns ratio). As anon-limiting example, a suitable size of the core may be in the range ofa few inches to about 20 inches in length and height and few inches toabout 10 inches in width and can be in any shape capable of fittingwithin the housing dimensions. Non-limiting examples of suitablematerials for forming the core include conductive, magnetic, highlypermeable, metallic material with low coercivity and hysteresis, such asiron (ferrite), steel, silicon, or any combination thereof. As anon-limiting example, the wire gauge of the wire windings around thecore of the transformer may range from about 10 gauge to about 32 gauge.As a non-limiting example, the thickness of the wire insulationsurrounding wire forming the core may range from about 1 mm to about 10cm thick. As a non-limiting example, the primary to secondary ratio ofthe core may range from about 25:1 (25 to 1), seen in FIG. 4A to about75:1 (75 to 1), seen in FIG. 4, though it should be understood by aperson skilled in the art that this ratio can change dependent on thesecondary load requirement, the form factor of the housing, and thesource voltage. These and other properties should be sufficient totransform the high line voltage (Vsource) to a lower output AC voltage.

Continuing to refer to FIGS. 4 and 4A, the secondary winding 24 b of thetransformer 24 in the transformation circuit 20 sits at line potentialso that it has a floating ground reference. As a result, while it mayappear that the transformation circuit 20 steps down the line voltage(Vsource), the transformation circuit 20 steps up the line voltage by avoltage factor, which is relatively small compared to the line voltage(Vsource). For example, in the exemplary embodiment shown in FIG. 4, thevoltage factor is about 48 VAC such that the output voltage (Vf) of thetransformation circuit 20 is about 8.708 VAC (i.e., 8.66 kV single phaseline voltage plus 48 VAC output) with reference to actual ground.

The resistor 22 and the transformer 24 of the transformation circuit 20shown in FIGS. 4 and 4A create an impedance-matched voltage divider. Asnoted above, the properties of the resistor 22 and the transformer 24can vary and can be selected based upon the input line voltage(Vsource), the high continuous input power, the desired output voltage(Vf) and the desired output wattage of the voltage harvesting device 10.As a non-limiting example, for a transformation circuit 20 rated for an8.66 kV single-phase voltage (15 kV three-phase voltage), the resistor22 may be sized from about 500 kΩ to about 2 MΩ in order to provide avoltage drop of about 7400 VAC, at about 60 W to about 100 W continuouswatts. In addition, the properties for the transformer 24 may bedesigned with a 75:1 ratio (FIG. 4) and a 25:1 (FIG. 4A), using asilicon steel or equivalent core with 22-gauge wire having an insulationthickness of about 2 mm, in order to provide a 1200V drop across theprimary windings of the transformer 24. It is noted that a higher turnsratio may be utilized to reduce the continuous wattage across theresistor 22.

Referring again to FIGS. 1 and 2, an exemplary embodiment of the housing50 of the voltage harvesting device 10 is shown. The housing 50 may comein various shapes and sizes depending upon a number of factors,including the components, e.g., the resistor 22 and the transformer 24,used in the transformation circuit 20, the source line voltage(Vsource), the desired output voltage of the voltage harvestingcircuitry, and the desired output power of the voltage harvestingcircuitry. Generally, as a non-limiting example, the dimensions of thehousing 50 may range from about 12″×5″×5″ to about 15″×8″×8″ or larger,dependent on the core dimensions of the transformer 24. As a specificexample, for an 8.66 kV single-phase line voltage, the resistor 22 maybe about 13 inches in length, about 4 inches in width and about 5 inchesin height, and the transformer 24 may be about 10 inches in length,about 3-4 inches in width and about 2 inches in height, which wouldresult in a housing 50 of about 8 inches in length, about 3 inches inwidth and about 1 inches in height.

Continuing to refer to FIGS. 1 and 2, the housing 50 may have a flatupper surface 50 a that permits a distribution component 100, e.g., arecloser, to be connected to the housing 50, as seen in FIGS. 11 and 12.The housing 50 may have a flat lower surface 50 b that permits thevoltage harvesting device 10 to be connected to a mounting structure110, as seen in FIGS. 11 and 12. A terminal connector 52 may extendingfrom the housing 50 and can be used to connect the input side of thevoltage harvesting device 10 to the line voltage (Vsource). A terminal54, e.g., a pin terminal, may also extend from the housing 50 and can beused to connect the output side of the voltage harvesting device 10 to asubsequent component, such as an overvoltage circuit 28, a voltageconverter 30 or a control device 102, e.g., a low wattage controldevice, described below and seen in FIG. 3.

The transformation circuit 20 of the voltage harvesting circuitry may bepotted or otherwise formed in an insulating material forming the housing50. Non-limiting examples of insulating materials include,cycloaliphatic epoxy, resin, polymer, porcelain and/or other insulatingmaterial known in the art that is durable, weather resistant and thatallows for sufficient dissipation of heat generated by thetransformation circuitry 20, such as through sheds 56 of variousdiameters, seen in FIGS. 1 and 2.

Referring again to refer to FIGS. 3 and 4, the transformation circuitry20 described above forms the voltage harvesting circuitry within thevoltage harvesting device 10. To protect the voltage harvesting device10 from excessive voltages and transients, a first overvoltagedisconnect device 26 may be connected to the input side of thetransformation circuitry 20. In other words, the first overvoltagedisconnect device 26 may be connected between the line voltage (Vsource)and the transformation circuitry 20. The first overvoltage disconnectdevice 26 would be provided to protect the transformation circuit 20from overvoltage conditions, such as those caused by transients, faultsor other disturbances on the line as is known in the art. Non-limitingexamples of the first overvoltage disconnect device 26 include,daisy-chained TVS diodes, FETs, PTC fuses, and/or similar components andassociated circuitry capable of providing overvoltage protection. In theexemplary embodiment of FIG. 4, the first overvoltage disconnect device26 is a series of daisy-chained TVS diodes or similar circuit connectedin parallel with the transformation circuit 20.

An optional second overvoltage disconnect device 28 may be connected tothe output side of the transformation circuitry 20, i.e., between theoutput of the transformation circuit 20 and subsequent circuitry coupledto the voltage harvesting device 10. The second overvoltage disconnectdevice 28 may be provided to protect the output side of thetransformation circuit 20 from overvoltage conditions, so that largeline voltage or current disturbances are not experienced across thesecondary of the transformation circuit 20 as is known. Non-limitingexamples of the second overvoltage disconnect device include,daisy-chained bidirectional TVS diodes, FETs, fuse, PTC fuses, diodes,and/or similar components and associated circuitry capable of providingovervoltage and overcurrent protection. In the exemplary embodiment ofFIG. 4, the second overvoltage disconnect device 28 is a series ofdaisy-chained bidirectional TVS diodes connected in parallel with theoutput of the transformation circuit 20 as shown. In one embodiment, thesecond overvoltage disconnect 28 may be included within the controldevice 102 instead of the voltage harvesting device circuitry.

To convert the output AC voltage (Vf) of the transformation circuit 20to a DC voltage for the control device 102, a voltage converter 30 maybe connected to the voltage harvesting device 10 or the optional secondovervoltage disconnect device 28. The voltage converter 30 may be aconventional AC/DC converter or other device or circuitry capable forconverting AC voltage to DC voltage. In the exemplary embodiment of FIG.4, the voltage converted 30 converts the 48 VAC output (Vf) from thetransformation circuit 20 to provide a 48 VDC operating voltage for thecontrol device 102. In the exemplary embodiments of FIGS. 9 and 10, thevoltage converter 30 converts the 48 VAC output voltage (Vf) from thetransformation circuit 20 to provides a 5 VDC operating voltage at 2.5watts for the control device 102.

The circuit of FIG. 4, with a line voltage (Vsource) of 8.66 kV ACoperates in the following manner. The line voltage (Vsource) is fed intothe transformation circuit 20 having a 1 MΩ resistor 22 and the groundis earth ground, via e.g., a utility pole ground. The voltage dropacross the resistor 22 reduces the 8.66 kV to 1.2 kV, which is a voltagedrop of about 7400V. The 1.2 kV is fed to the transformer 24 (havingapproximately a 25:1 primary to secondary ratio), which drops the 1.2 kVto output a voltage (Vf) of about 48 VAC at about 10 W. That is, thesecondary of the transformer 24 in the transformation circuit 20 outputsabout 48 VAC at 10 W. The impedance of the resistor 22 and thetransformer 24 should be matched so that the wattage created from thecurrent flowing through the transformation circuit 20 does not drop. Itis noted that in the configuration shown, the secondary of thetransformer and the remaining portions of the circuit are held at linepotential, acting as floating ground reference. As a result, the outputof the transformation circuit 20 (Vf) is approximately 8708V. However,with the floating ground being at approximately 8.66 kV the effectiveoutput voltage of the transformation circuit 20 is about 48 VAC. Thus,the additional step ‘up’ from the line voltage potential is whatachieves the voltage harvesting from the line potential whether or notthere is a load present on the line. The output voltage (Vf) of thetransformation circuit 20, e.g., the 48 VAC, is then input into the ACto DC converter 30 which can have characteristics that convert the 48VAC to the same or a lower DC voltage so that the converter outputs a DCvoltage for a prescribed application as is known. For example, to powera control device 102 that is a communication radio for a recloser as thedistribution component 100, may require approximately 5 VDC at 2.5 W. Insuch an example, the voltage converter 30 would be configured to convertthe 48 VAC at about 10 W to 5 VDC at about 2.5 W. The 5 VDC at about 2.5W output of the voltage converter 30 is then fed into the communicationradio 102, also sitting at line potential, to continuously power thecommunication radio 102 whether or not a load current is present on theline.

As noted above, in the event line voltage exceeds a certain threshold,e.g., 95 kV, the first overvoltage disconnect device 26 would short toeffectively disconnect the transformation circuit 20 from the lineovervoltage condition This overvoltage value may be higher or lowerdepending on, for example, the corresponding rated line voltage(Vsource) where it is being utilized, the amount of the voltage seenacross the primary winding of the transformer (or resistor, depending onwhich circuit is being considered, e.g., FIGS. 4, 6, 8 or FIGS. 4A, 6A,8A). As noted above, in the event the secondary voltage or current,i.e., on the output side of the transformation circuit 20, exceeds acertain threshold, e.g., 50V to 8.6 kV, the second overvoltagedisconnect device 28 would short to effectively disconnect thetransformation circuit 20 from the output side overvoltage condition.The secondary overvoltage disconnect includes a range of values thatdepend on, for example, the nominal line voltage of the line on which itis utilized and the output voltage being supplied to the converter. Thesecond overvoltage disconnect serves to protect the additionalcomponents, i.e., the AC/DC converter 30 and control device 102 in thecase where the transformer or resistor/capacitor/inductor fails or inthe case of an overvoltage event on the line which effectively raisesthe ‘ground’ line potential of the circuit.

Turning now to FIGS. 5, 6, 6A, 7, 8 and 8A, additional exemplaryembodiments of the circuitry that may be included in the voltageharvesting device 10 according to the present disclosure are shown. Inthe exemplary embodiment of FIGS. 5, 6 and 6A, the voltage harvestingcircuitry includes the overvoltage disconnect 26. The overvoltagedisconnect 28 may or may not be included in the voltage harvestingcircuitry, and the voltage converter 30 is external to the voltageharvesting device 10. In the exemplary embodiment of FIGS. 7, 8 and 8A,the voltage harvesting circuitry includes the overvoltage disconnect 26and the voltage converter 30. The overvoltage disconnect 28 may or maynot be included in the voltage harvesting device 10.

Referring to FIGS. 9 and 10, exemplary embodiments of a single-phasepower distribution system architecture incorporating the voltageharvesting device according to the present disclosure are shown. In theexemplary embodiment of FIG. 9, the distribution component 100 is arecloser, the control device 102 is a recloser peripheral device, suchas a communication module, and the voltage harvesting device 10 includesone of the embodiments shown in FIGS. 8 and 9. The voltage harvestingdevice 10 can be mounted to a utility pole and the recloser 100 can bemounted to one end of the voltage harvesting device 10, as seen in FIGS.11 and 12. The voltage harvesting device 10 is connected to the linephase conductor having a line voltage (Vsource), e.g., an 8.66 kV sourceline voltage. When triggered, the recloser 100 would open, disconnectingthe load from the line voltage (Vsource). Whether the recloser 100 isclosed or open, the line voltage (Vsource) is fed to the voltageharvesting device 10 from the source side, which transforms the linevoltage (Vsource), e.g., the 8.66 kV to 48 VAC at 10 watts, and thevoltage converter 30 converts the 48 VAC to 5 VDC at 2.5 watts. The 5VDC at 2.5 watts is output by the voltage harvesting device 10 and fedto the recloser communication module 102 which can be used tocommunicate and power a control element for the operation of therecloser 100 via an interface, such as a serial port or hardwireconnection, or wireless connection (see, FIG. 10) between the reclosercommunication module 102 and the recloser 100. In one embodiment, thecommunication module 102 can be utilized to provide power to chargecapacitors or other energy storage elements in the recloser in order toperform functions, such as closing or opening the device after an opencircuit or unloaded condition.

In the exemplary embodiment of FIG. 10, the distribution component 100is a recloser, the control device 102 is a recloser wirelesscommunication and/or control device, such as an RTU, and the voltageharvesting device 10 includes one of the embodiments shown in FIGS. 8and 9. The voltage harvesting device 10 can be mounted to a utility poleand the recloser 100 can be mounted to one end of the voltage harvestingdevice 10, as seen in FIGS. 11 and 12. The voltage harvesting device 10is connected to a single phase line conductor having a line voltage(Vsource), e.g., an 8.66 kV line voltage. When triggered, the recloser100 would open, disconnecting the load from the line voltage (Vsource).Whether the recloser 100 is closed or open, the source line voltage(Vsource) is fed to the voltage harvesting device 10 which transformsthe line voltage (Vsource), e.g., the 8.66 kV, to 48 VAC at 10 watts andthe voltage converter 30 converts the 48 VAC to 5 VDC at 2.5 watts. The5 VDC at 2.5 watts is output by the voltage harvesting device 10 and fedto the communication and/or control device 102 which may control theoperation of the recloser 100 via wireless communication between thecommunication and/or control device 102 and the recloser 100 using knowncommunication techniques and protocols.

In another exemplary embodiment described with reference to FIG. 10, thecontrol device 102 may be independent of the distribution component 100or may be a distribution component itself, having additional circuitrywithin it to communicate and transmit or indicate data regarding lineconditions.

Referring to FIGS. 13 and 14, an exemplary embodiment of a three-phasepower distribution system architecture incorporating the voltageharvesting device according to the present disclosure is shown. In thisexemplary embodiment, each phase (1, 2, or 3) of a three-phase line isfed into a separate voltage harvesting device 10, the output of which isfed to a separate control device 102, such as an RTU, which controls oneor more separate distribution components 100 similar to that shown inFIGS. 9 and 10 and described above. In the embodiment of FIG. 13 thecontrol devices 102 are hardwired to the distribution component 100. Inthe embodiment of FIG. 14 a control device 102 (e.g., an RTU) wirelesslycommunicates with multiple distribution components 100 and is poweredvia one or more of the voltage harvesting devices 10 on each of themultiple distribution components 100

The voltage harvesting device according to the present disclosure may beused with live ungrounded devices or with pole-based control devices,which are usually grounded. It will be understood that variousmodifications can be made to the embodiments of the present disclosurewithout departing from the spirit and scope thereof. All values setforth herein are exemplary and can be modified depending upon the linevoltage (Vsource) and line continuous wattage, the voltage and powerrequirements of the control device, and the characteristics andproperties of the voltage harvesting device. This includes the valuesfor the physical dimensions and the resistance and power characteristicsof the resistor and transformer and other elements used with orincorporated into the voltage harvesting device, such as the overvoltagedisconnects and the voltage converter. Additionally, though the voltageharvesting circuitry within the voltage harvesting device may onlyinclude the transformation circuit, i.e., the resistor/transformervoltage divider, the voltage harvesting circuitry may also include otherelements, such as the first overvoltage disconnect device, the secondovervoltage disconnect device and/or the voltage converter. Therefore,the above description should not be construed as limiting thedisclosure, but merely as embodiments thereof. Those skilled in the artwill envision other modifications within the scope and spirit of theinvention as defined by the claims appended hereto.

Referring now to FIGS. 15-18 additional exemplary embodiments of thetransformation circuitry 20 according to the present disclosure areshown. These exemplary embodiments of the transformation circuitry 20may be substituted for the transformation circuitry 20 described hereinabove. In the exemplary embodiment of FIG. 15, the transformationcircuitry 20 includes an inductor 106 and the transformer 24. Thetransformer 24 is connected between the line voltage (Vsource) and oneside of the inductor 106, as shown. The other side of the inductor 106is connected to pole ground. It is noted that pole ground is earthground, actual ground or the like. In the exemplary embodiment of FIG.15, the inductor 106 drops the line voltage (Vsource) by a large factordependent on the source line voltage. For example, using a 1.3 kHinductor 106 and a transformer 24 with a 75:1 turns ratio, a 15 kVsingle phase line voltage or 8.66 kV, may be dropped by a factor rangingbetween about 4.0 kV to about 7.5 kV across the inductor 106. Thevoltage drop factor may range from about 45-95% of the single phasesource voltage. Further, since the inductor 106 is connected in serieswith the primary winding 24 a of the transformer 24, the inductor 106 issubjected to and configured to handling a high continuous wattage. Thewattage is dependent upon a number of factors including the inductorsize and construction, e.g., parallel configuration. As an example, thehigh continuous wattage may be in the range of between about 20 W toabout 100 W. However, this wattage may change dependent on the linevoltage and the output requirements of the circuit. As a non-limitingexample, for a single-phase line voltage of 8.6 kV the high continuouswattage may be about 60 W.

In the exemplary embodiment of FIG. 16, the transformation circuitry 20includes a capacitor 110 and the transformer 24. The transformer 24 isconnected between the line voltage (Vsource) and one side of thecapacitor 110, as shown. The other side of the capacitor 110 isconnected to pole ground. It is noted that pole ground is earth ground,actual ground or the like. In the exemplary embodiment of FIG. 16, thecapacitor 110 drops the line voltage (Vsource) by a large factordependent on the source line voltage. For example, using a 5.0 nFcapacitor 110 and a transformer 24 with a 75:1 turns ratio, a 15 kVsingle phase line voltage or 8.66 kV, may be dropped by a factor rangingbetween about 4.0 kV to about 7.5 kV across the capacitor 110. Thevoltage drop factor may range from about 45-95% of the single phasesource voltage. Further, since the capacitor 110 is connected in serieswith the primary winding 24 a of the transformer 24, the capacitor 110is subjected to and configured to handling a high continuous wattage.The wattage is dependent upon a number of factors including the inductorsize and construction, e.g., parallel configuration. As an example, thehigh continuous wattage may be in the range of between about 20 W toabout 100 W. However, this wattage may change dependent on the linevoltage and the output requirements of the circuit. As a non-limitingexample, for a single-phase line voltage of 8.6 kV the high continuouswattage may be about 60 W.

In the exemplary embodiment of FIG. 17, the transformation circuitry 20includes a parallel resistor network 114 and the transformer 24. Theparallel resistor network 114 includes two resistors R_(A) and R_(B).The transformer 24 is connected between the line voltage (Vsource) andone side of the parallel resistor network 114, as shown. The other sideof the parallel resistor network 114 is connected to pole ground. It isnoted that pole ground is earth ground, actual ground or the like. Inthe exemplary embodiment of FIG. 17, the parallel resistor network 114drops the line voltage (Vsource) by a large factor dependent on thesource line voltage. For example, using two 500 KΩ resistors R_(A) andR_(B) and a transformer 24 with a 75:1 turns ratio, a 15 kV single phaseline voltage or 8.66 kV, may be dropped by a factor ranging betweenabout 4.0 kV to about 7.5 kV across the parallel resistor network 114.The voltage drop factor may range from about 45-95% of the single phasesource voltage. Further, since the parallel resistor network 114 isconnected in series with the primary winding 24 a of the transformer 24,the parallel resistor network 114 is subjected to and configured tohandling a high continuous wattage. The wattage is dependent upon anumber of factors including the inductor size and construction, e.g.,parallel configuration. As an example, the high continuous wattage maybe in the range of between about 20 W to about 100 W. However, thiswattage may change dependent on the line voltage and the outputrequirements of the circuit. As a non-limiting example, for asingle-phase line voltage of 8.6 kV the high continuous wattage may beabout 60 W.

In the exemplary embodiment of FIG. 18, the transformation circuitry 20includes a parallel resistor and a series resistor network 118 and thetransformer 24. The parallel resistor and a series resistor network 118may also be referred to herein as the resistor network 118. The resistornetwork 118 includes two resistors R_(A) and R_(B) in parallel and aresistor R_(C) in series with the two parallel resistors R_(A) andR_(B). In other exemplary embodiments, the resistor network 118 mayinclude two or more individual resistors, e.g., resistors R_(A) andR_(C), in series. The transformer 24 is connected between the linevoltage (Vsource) and one side of the resistor network 118, as shown.The other side of the resistor network 118 is connected to pole ground.It is noted that pole ground is earth ground, actual ground or the like.In the exemplary embodiment of FIG. 18, the resistor network 118 dropsthe line voltage (Vsource) by a large factor dependent on the sourceline voltage. For example, using three 500 KΩ resistors R_(A), R_(B) andR_(C) and a transformer 24 with a 75:1 turns ratio, a 15 kV single phaseline voltage or 8.66 kV, may be dropped by a factor ranging betweenabout 4.0 kV to about 7.5 kV across the parallel resistor network 114.The voltage drop factor may range from about 45-95% of the single phasesource voltage. Further, since the parallel resistor network 114 isconnected in series with the primary winding 24 a of the transformer 24,the parallel resistor network 114 is subjected to and configured tohandling a high continuous wattage. The wattage is dependent upon anumber of factors including the inductor size and construction, e.g.,parallel configuration. As an example, the high continuous wattage maybe in the range of between about 20 W to about 100 W. However, thiswattage may change dependent on the line voltage and the outputrequirements of the circuit. As a non-limiting example, for asingle-phase line voltage of 8.6 kV the high continuous wattage may beabout 60 W.

As shown throughout the drawings, like reference numerals designate likeor corresponding parts. While illustrative embodiments of the presentdisclosure have been described and illustrated above, it should beunderstood that these are exemplary of the disclosure and are not to beconsidered as limiting. Additions, deletions, substitutions, and othermodifications can be made without departing from the spirit or scope ofthe present disclosure. Accordingly, the present disclosure is not to beconsidered as limited by the foregoing description.

What is claimed is:
 1. A voltage harvesting device for use in powerdistribution systems, the voltage harvesting device comprising: ahousing; and a transformation circuit within the housing, thetransformation circuit including at least one first impedance componentand at least one second impedance component, the at least one firstimpedance component having: a positive input capable of beingelectrically coupled to a loaded or unloaded source line voltage; anegative input electrically coupled to the at least one second impedancecomponent; and an output capable of being coupled to a device, whereinthe output and the device both reference a floating ground of the loadedor unloaded source line voltage; wherein the first impedance componentand the second impedance component are arranged as a voltage divider,the voltage divider producing an AC voltage on the output of the firstimpedance component that is a higher voltage than the loaded or unloadedsource line voltage.
 2. The voltage harvesting device according to claim1, wherein the second impedance component is coupled to actual ground.3. The voltage harvesting device according to claim 2, furthercomprising a first overvoltage disconnect component electrically coupledbetween the positive input of the at least one first impedance componentand actual ground.
 4. The voltage harvesting device according to claim3, wherein the first overvoltage device comprises one or moredaisy-chained bi-directional TVS diodes, FETs, or PTC fuses.
 5. Thevoltage harvesting device according to claim 1, further comprising asecond overvoltage disconnect device electrically coupled across theoutput of the at least one first impedance component.
 6. The voltageharvesting device according to claim 5, wherein the second overvoltagedevice comprises one or more daisy-chained bi-directional TVS diodes,FETs, or PTC fuses.
 7. The voltage harvesting device according to claim1, further comprising a converter electrically coupled to the output ofthe at least one first impedance component that converts the AC outputvoltage of the at least one first impedance component to a DC voltage.8. The voltage harvesting device according to claim 1, wherein the atleast one first impedance component is a transformer.
 9. The voltageharvesting device according to claim 1, wherein the at least one secondimpedance component is a resistor.
 10. The voltage harvesting deviceaccording to claim 1, wherein the at least one second impedancecomponent comprises a parallel resistor network.
 11. The voltageharvesting device according to claim 1, wherein the at least one secondimpedance component comprises two or more parallel resistors and aseries resistor.
 13. The voltage harvesting device according to claim 1,wherein the at least one second impedance component comprises two ormore resistors in series.
 14. A voltage harvesting device for use inpower distribution systems, the voltage harvesting device comprising: ahousing; and a transformation circuit within the housing, thetransformation circuit including: a transformer having a primary sidewith a first input terminal electrically connected to a loaded orunloaded line voltage source and a second input terminal, and asecondary side of the transformer having a first output terminal capableof being electrically connected to a floating ground referenced to theloaded or unloaded source line voltage and a second output terminalcapable of producing an AC voltage above the voltage of the loaded orunloaded line voltage source; and at least one resistor having a firstterminal electrically connected to the second input terminal of thetransformer and a second terminal connected to actual ground.
 15. Thevoltage harvesting device of claim 14, wherein the AC voltage producedby the second output terminal of the transformer is in the range ofabout 25 VAC to 250 VAC relative to the loaded or unloaded line voltagesource.
 16. The voltage harvesting device according to claim 14, furthercomprising a first overvoltage disconnect device electrically coupledbetween the first input terminal of the transformer and the secondterminal of the resistor.
 17. The voltage harvesting device according toclaim 16, wherein the first overvoltage device comprises one or moredaisy-chained bi-directional TVS diodes, FETs, or PTC fuses.
 18. Thevoltage harvesting device according to claim 14, further comprising asecond overvoltage disconnect device electrically coupled between thefirst and second output terminals of the secondary side of thetransformer.
 19. The voltage harvesting device according to claim 18,wherein the second overvoltage device comprises one or moredaisy-chained bi-directional TVS diodes, FETs, or PTC fuses.
 20. Thevoltage harvesting device according to claim 14, further comprising aconverter electrically coupled between the first and second outputterminals of the secondary side of the transformer that converts the ACoutput voltage across the first and second output terminals of thesecondary side of the transformer to a DC voltage.